Early stages of career at University College, London. War work at admiralty Signals Establishment-Hashmere. Work on infrared for Admiralty. First work on germanium, 1953-1954. Work on indium arsenide and gallium antimonide from 1956. Interaction with Christopher Rose-Innis. Differences between semiconductor research in U.K. and U.S. Some 1960s work on lasers and Gunn effect at RSRE-Malvern. Overview of semiconductors work at RSRE-Malvern.